1. Field of the Invention
The present invention relates to a pneumatic/hydraulic balance weight system for mother machines, and more particularly to a pneumatic/hydraulic system for balancing a processing unit of a mother machine to thereby allow rapid, precise control of the processing unit.
2. Description of the Related Art
In industries, the processing units of many processing machines or mother machines are frequently moved, and it is difficult for the operator to rapidly, precisely control movements of the processing units that often weight more than one ton. FIG. 4 of the drawings illustrates a mother machine 40 in which the processing unit 44 thereof is balanced by a weight 41 (which generally has a weight approximately the same as that of the processing unit 44) via a chain 43 and gears 42. However, the weight 41 is bulky and thus causes other problems in manufacture and installation thereof. In addition, potential risk of injury to people exists as the supporting effect of the chain/gear system for supporting the heavy weight 41 and the processing unit 44 is doubtful.
FIG. 5 of the drawings illustrates an improved system that uses a hydraulically driven piston rod 551 to retain a processing unit 56 of a mother machine 50. The piston rod 551 includes an end slidably received in a cylinder 55 that is communicated to a tank 51 via a hydraulic/electromagnetic valve 54. For lifting the processing unit 56, a motor 52 drives a pump 53 to pump oil 511 in the tank 51 into a lower end of the cylinder 55 via line B, while gas in the upper end of the cylinder 55 flows to the valve 54 via line A. Lowering of the processing unit 56 is achieved by outputting gas from the valve 54 to the upper end of the cylinder 55 via line A, while hydraulic oil flows to the valve 54 via line B.
However, the tank 51 occupies a considerable space, and the hydraulic device often leaks and generates noise. In addition, control by the hydraulic device and the hydraulic/electromagnetic valve consumes considerable electricity, and the movement of the processing unit is very slow. Further, the control elements are numerous and thus are difficult to maintain.
The present invention is intended to provide a balance weight system to mitigate an/or obviate the above problems.